Non-penetrating brain injuries carry devastating potential for cognitive, neurologic, and socioemotional disease, but no current approach reliably identifies this type of brain injury or its severity. For example, the current standard for concussion diagnosis is largely subjective in that it relies on accurate symptom reporting by the patient. Thus, there are ongoing efforts to identify objective markers to assist in diagnosing a concussion and predicting recovery.
One area of focus is on cerebrospinal fluid- and blood-based biomarkers that test for sequelae of neural injury. However, these biomarkers are invasive and may not extend to milder forms of non-penetrating brain injury, such as concussions. A second area tries to adopt neuroimaging techniques, such as diffusion tensor imaging and functional magnetic resonance imaging, to detect concussions. However, these approaches rely on expensive equipment and contradictory results are often reported: for example, both increases and decreases in white matter volume have been associated with mild traumatic brain injury. Visual, auditory, and somatosensory evoked potentials have all been explored in individuals following head injury, but contradictory findings have been reported. (Folmer, et al. Int. J. Psychophysiol. 82, 4-15 (2011); Munjal, et al. J. Trauma Acute Care Surg. 68, 13-18 (2010); Gosselin, N. et al. Neurosurg. Focus 33, E7 (2012)) Overall, current neuroimaging and electrophysiological approaches for various forms of non-penetrating brain injury show group differences but overlap between groups potentially thwarts evaluation of individual differences. The limitations of the aforementioned approaches necessitate a fresh methodology that has granularity into the biological minutiae of sound processing, and one that reliably indicates individual differences.